BUD ~ Smart Application Board for BOB-4

  BUD-1H shown with optional BOB-4H module installed

BUD-1HG shown with optional BOB-4HGI module installed
This product is no longer being manufactured.

BUD is a compact ‘buddy’ board for the BOB-4 video information overlay module, with enough embedded processing power and peripheral support to completely implement many applications. Example software allows first-time users to immediately exercise the combined functionality of BUD and BOB-4 with programs such as GPS data display, TV Typewriter, and Real Time Clock display. BUD also serves as a general-purpose Atmel ATmega640 (AVR series) microcontroller developer board, with or without the piggyback BOB-4 module. With BOB-4 installed, BUD easily generates complex text and graphics displays on conventional TV monitors.

Key Features:


BUD's processor is an Atmel AVR-series ATmega640 running on 5V power at 14.7456 MHz. This microcontroller chip has much to offer embedded system developers, including 64KB of in-system programmable (ISP) flash memory, numerous on-board peripherals, and impressive execution speed resulting from its full-instruction-cycle per clock cycle core design. BUD ships with an RS-232 serial bootloader installed, so it’s unnecessary to purchase additional device programming equipment. Atmel’s free AVR Studio, the free AVR-GCC compiler, and a number of low-cost BASIC compilers support AVR software development.


Many of the processor’s most useful I/O pins are brought to a 40-pin general purpose I/O (GPIO) header for convenient application hookup. Except for PG5, which drives an LED, remaining processor I/O pins not dedicated to internal functions are brought to customer installable pin headers.

Serial com:

Four USARTs are available on the ATmega640. One is committed to internal BOB-4 communication. A second USART is interfaced for direct connection to a PC COM port. The two remaining USARTs are brought out to the GPIO header, along with an industry-standard RS-232 hardware interface hookup option. USARTs support RS-232-style async communication as well as synchronous communication standards such as SPI.


Four of the processor’s port F analog voltage input pins, and all eight pins of port K are brought to the GPIO connector. The 10-bit ADC is furnished with a precision on-board voltage reference of 4.096V, which defines the upper limit for direct voltage measurement. To support ratiometric measurement, this voltage reference is also available as a dedicated output on the GPIO port.

Data memory:

The processor has 4KB of on-board EEPROM. An optional Atmel AT45-series DataFlash memory chip is attached to the processor’s SPI port. As an example, 4MB of user data memory would be available with an AT45DB321D installed in this position. A second optional DataFlash chip may be installed for BOB-4 custom font memory expansion.


An NJU6355 real-time clock chip is linked to BUD’s processor via ordinary I/O pins. Timekeeping power may come from an optional on-board lithium coin cell or from an off-board source, through the power supply connector.


BUD operates on 6~12VDC unregulated power supply voltages. It consumes about 150mA with a BOB-4H module attached and operating normally, or about 43mA without. The internally regulated +5V supply is available at two locations on the GPIO connector.

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BUD Information Resources

BUD Application Guide (PDF):  Preliminary release. Please report any discrepancies.

BUD Schematic Drawing (PDF):  Use with App Guide.

BUD Software Example Package (ZIP) 

Smart Encoder Interface (PDF):  SEI implements a quadrature distance encoder and operator control interface for BOB-4 in an Atmel ATmega88 microcontroller. It was written to drive BOB-4 through the SPI port, so modification is necessary to make it compatible with the 'TTL-232' interface to BOB-4 and the ATmega640 processor in BUD. Here's the AVR-GCC Source Code (ZIP) for SEI.


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